What ImmalvanoM here is saying actually makes the most sense given the context of Jinbei's commentary, if Jinbei's words is taken as an isert from Oda himself. I suspsect Oda will be questioned about this in SBS.
If the Seraphim was made with DNA extracted from Hancock before Hancock encountered Luffy, the answer is NOT "Well Hancock's genes are predisposed towards Luffy" - that actually makes no sense, or else real Hancock would have immediately fallen for Luffy without needing him to "prove himself", (Similar to Sanji with ladies) without any major interaction or display of noble character - but instead Luffy's character speaks to Hancock's heart through said displays, i.e. trying to save Hancock's underlings.
For Seraphim copy to be having a crush on Luffy would make no sense IF it its character is going 1:1 off of Hancock because it simply did not have enough opportunity to witness Luffy's character traits in action to come to a conclusion of affection.
However, here's where it gets confusing. The reality is this. Seraphim Hancock or S-Snake is not 1:1 Hancock. In other words, as far as we know S-Snake never suffered under perverted/horny male Celestial Dragons or the same level of exposure to negative elements associated with unbridled or unrefined masculinity, which is exactly what caused Hancock to be so moved by the image of a male character with more pure/self-sacrificing motives more impactful, namely Luffy.
There is another layer of complexity here. The moral framework of S-Snake. If you look closely, you notice that Luffy, though he looked concerned and stressed, asked S-Snake (addressed her as Hancock) to undo her petrification - he did not *demand* or *command* it.
It seems unlikely that S-Snake would fall in love with Luffy's character traits as Boa did since the amount of interaction and events witnessed are drastically less - asking for her to do something instead of demanding it is nice, sure... but its not really all that impressive. But if it has indeed happened, the most likely explanation is that the S-Snake was used to having her will stomped on by being ordered around by superiors (authority chip hierarchy) or commanded to do things - so having Luffy instead "ask" her immediately struck those affection or desire nerves, if you will. She feels Luffy "Actually cares" compared to the others, and that makes him stand out as a sort of romantic referent, as it were.